An image forming apparatus of an electrophotographic system typically employs an electrophotographic photoreceptor in which a film of a functional layer including a photosensitive layer is formed on the outer peripheral surface of a cylindrical substrate. In some cases, characteristics of a photosensitive layer of an electrophotographic photoreceptor having such a configuration vary depending on a state of a substrate and conditions during film formation. In such cases, an electrophotographic photoreceptor having such a configuration influences image properties of an image forming apparatus including such an electrophotographic photoreceptor. Accordingly, an electrophotographic photoreceptor which is designed suitable for and dedicated for an image forming apparatus needs to be included in the image forming apparatus.
As an identification method of an electrophotographic photoreceptor, for example, a method of providing an individual identification code on a spigot joint portion which is provided at an end portion in the axial direction of a substrate has been proposed (see WO2008/078783, Japanese Unexamined Patent Application Publication No. 2009-48206). However, in this case, since an identification code is formed inside the substrate, there have been problems such as that it is difficult to perform individual identification when driving flanges are attached on both ends of a photoreceptor and that it is necessary to provide a manufacturing process dedicated for forming an identification code.